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Use Cases for Data Center Network Virtualization Overlays

The information below is for an old version of the document.
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This is an older version of an Internet-Draft that was ultimately published as RFC 8151.
Expired & archived
Authors Lucy Yong , Mehmet Toy , Aldrin Isaac , Vishwas Manral , Linda Dunbar
Last updated 2016-04-18 (Latest revision 2015-10-16)
Replaces draft-mity-nvo3-use-case
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Additional resources Mailing list discussion
Stream WG state WG Document
Revised I-D Needed - Issue raised by WG, Waiting for Referencing Document
Document shepherd Benson Schliesser
IESG IESG state Became RFC 8151 (Informational)
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Network Working Group                                           L. Yong
Internet Draft                                                   Huawei
Category: Informational                                          M. Toy
                                                               A. Isaac
                                                              V. Manral
                                                         Ionos Networks
                                                              L. Dunbar

Expires: April 2016                                  October 16, 2015

         Use Cases for Data Center Network Virtualization Overlays



   This document describes Data Center (DC) Network Virtualization over
   Layer 3 (NVO3) use cases that can be deployed in various data
   centers and serve different applications.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with
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   This Internet-Draft will expire on April 18, 2016.

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Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   ( in effect on the date of
   publication of this document. Please review these documents
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   warranty as described in the Simplified BSD License.

Table of Contents

   1. Introduction...................................................3
      1.1. Terminology...............................................4
   2. Basic Virtual Networks in a Data Center........................4
   3. DC Virtual Network and External Network Interconnection........6
      3.1. DC Virtual Network Access via the Internet................6
      3.2. DC VN and SP WAN VPN Interconnection......................7
   4. DC Applications Using NVO3.....................................8
      4.1. Supporting Multiple Technologies and Applications.........9
      4.2. Tenant Network with Multiple Subnets......................9
      4.3. Virtualized Data Center (vDC)............................11
   5. Summary.......................................................12
   6. Security Considerations.......................................13
   7. IANA Considerations...........................................13
   8. References....................................................13
      8.1. Normative References.....................................13
      8.2. Informative References...................................13
   Authors' Addresses...............................................15

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1. Introduction

   Server Virtualization has changed the Information Technology (IT)
   industry in terms of the efficiency, cost, and speed of providing
   new applications and/or services such as cloud applications. However
   traditional Data Center (DC) networks have some limits in supporting
   cloud applications and multi tenant networks [RFC7364]. The goal of
   Network Virtualization Overlays in the DC is to decouple the
   communication among tenant systems from DC physical infrastructure
   networks and to allow one physical network infrastructure to provide:

   o  Multi-tenant virtual networks and traffic isolation among the
      virtual networks over the same physical network.

   o  Independent address spaces in individual virtual networks such as
      MAC, IP, TCP/UDP etc.

   o  Flexible Virtual Machines (VM) and/or workload placement
      including the ability to move them from one server to another
      without requiring VM address and configuration changes, and the
      ability to perform a "hot move" with no disruption to the live
      application running on VMs.

   These characteristics of NVO3 help address the issues that cloud
   applications face in Data Centers [RFC7364].

   An NVO3 network may interconnect with another NVO3 virtual network,
   or another physical network (i.e., not the physical network that the
   NVO3 network is over), via a gateway. The use case examples for the
   latter are: 1) DCs that migrate toward an NVO3 solution will be done
   in steps, where a portion of tenant systems in a VN is on
   virtualized servers while others exist on a LAN. 2) many DC
   applications serve to Internet users who are on physical networks; 3)
   some applications are CPU bound, such as Big Data analytics, and may
   not run on virtualized resources. Some inter-VN policies can be
   enforced at the gateway.

   This document describes general NVO3 use cases that apply to various
   data centers. Three types of the use cases described in this
   document are:

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   o  Basic NVO3 virtual networks in a DC (Section 2). All Tenant
      Systems (TS) in the virtual network are located within the same
      DC. The individual virtual networks can be either Layer 2 (L2) or
      Layer 3 (L3). The number of NVO3 virtual networks in a DC is much
      higher than what traditional VLAN based virtual networks [IEEE
      802.1Q] can support. This case is often referred as to the DC
      East-West traffic.

   o  Virtual networks that span across multiple Data Centers and/or to
      customer premises, i.e., an NVO3 virtual network where some
      tenant systems in a DC attach to interconnects another virtual or
      physical network outside the data center. An enterprise customer
      may use a traditional carrier VPN or an IPsec tunnel over the
      Internet to communicate with its systems in the DC. This is
      described in Section 3.

   o  DC applications or services require an advanced network that
      contains several NVO3 virtual networks that are interconnected by
      the gateways. Three scenarios are described in Section 4: 1)
      using NVO3 and other network technologies to build a tenant
      network; 2) constructing several virtual networks as a tenant
      network; 3) applying NVO3 to a virtualized DC (vDC).

   The document uses the architecture reference model defined in
   [RFC7365] to describe the use cases.

1.1.  Terminology

   This document uses the terminologies defined in [RFC7365] and
   [RFC4364]. Some additional terms used in the document are listed

   DMZ: Demilitarized Zone. A computer or small sub-network that sits
   between a trusted internal network, such as a corporate private LAN,
   and an un-trusted external network, such as the public Internet.

   DNS: Domain Name Service [RFC1035]

   NAT: Network Address Translation [RFC1631]

   Note that a virtual network in this document refers to an NVO3
   virtual network in a DC [RFC7365].

2. Basic Virtual Networks in a Data Center

   A virtual network in a DC enables communications among Tenant
   Systems (TS). A TS can be a physical server/device or a virtual

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   machine (VM) on a server, i.e., end-device [RFC7365]. A Network
   Virtual Edge (NVE) can be co-located with a TS, i.e., on the same
   end-device, or reside on a different device, e.g., a top of rack
   switch (ToR). A virtual network has a virtual network identifier
   (can be globally unique or locally significant at NVEs).

   Tenant Systems attached to the same NVE may belong to the same or
   different virtual networks. An NVE provides tenant traffic
   forwarding/encapsulation and obtains tenant systems reachability
   information from a Network Virtualization Authority (NVA)[NVO3ARCH].
   DC operators can construct multiple separate virtual networks, and
   provide each with own address space.

   Network Virtualization Overlay in this context means that a virtual
   network is implemented with an overlay technology, i.e., within a DC
   that has IP infrastructure, tenant traffic is encapsulated at its
   local NVE and carried by a tunnel to another NVE where the packet is
   decapsulated and sent to a target tenant system. This architecture
   decouples tenant system address space and configuration from the
   infrastructure's, which provides great flexibility for VM placement
   and mobility. It also means that the transit nodes in the
   infrastructure are not aware of the existence of the virtual
   networks and tenant systems attached to the virtual networks. The
   tunneled packets are carried as regular IP packets and are sent to
   NVEs. One tunnel may carry the traffic belonging to multiple virtual
   networks; a virtual network identifier is used for traffic
   demultiplexing. A tunnel encapsulation protocol is necessary for NVE
   to encapsulate the packets from Tenant Systems and encode other
   information on the tunneled packets to support NVO3 implementation.

   A virtual network implemented by NVO3 may be an L2 or L3 domain. The
   virtual network can carry unicast traffic and/or multicast,
   broadcast/unknown (for L2 only) traffic from/to tenant systems.
   There are several ways to transport virtual network BUM traffic

   It is worth mentioning two distinct cases regarding to NVE location.
   The first is where TSs and an NVE are co-located on a single end
   host/device, which means that the NVE can be aware of the TS's state
   at any time via an internal API. The second is where TSs and an NVE
   are not co-located, with the NVE residing on a network device; in
   this case, a protocol is necessary to allow the NVE to be aware of
   the TS's state [NVO3HYVR2NVE].

  One virtual network can provide connectivity to many TSs that attach
  to many different NVEs in a DC. TS dynamic placement and mobility
  results in frequent changes of the binding between a TS and an NVE.

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  The TS reachability update mechanisms need be fast enough so that
  the updates do not cause any communication disruption/interruption.
  The capability of supporting many TSs in a virtual network and many
  more virtual networks in a DC is critical for the NVO3 solution.

   If a virtual network spans across multiple DC sites, one design is
   to allow the network to seamlessly span across the sites without DC
   gateway routers' termination. In this case, the tunnel between a
   pair of NVEs can be carried within other intermediate tunnels over
   the Internet or other WANs, or the intra DC and inter DC tunnels can
   be stitched together to form a tunnel between the pair of NVEs that
   are in different DC sites. Both cases will form one virtual network
   across multiple DC sites.

3. DC Virtual Network and External Network Interconnection

   Many customers (an enterprise or individuals) who utilize a DC
   provider's compute and storage resources to run their applications
   need to access their systems hosted in a DC through Internet or
   Service Providers' Wide Area Networks (WAN). A DC provider can
   construct a virtual network that provides connectivity to all the
   resources designated for a customer and allows the customer to
   access the resources via a virtual gateway (vGW). This, in turn,
   becomes the case of interconnecting a DC virtual network and the
   network at customer site(s) via the Internet or WANs. Two use cases
   are described here.

3.1. DC Virtual Network Access via the Internet

   A customer can connect to a DC virtual network via the Internet in a
   secure way. Figure 1 illustrates this case. The DC virtual network
   has an instance at NVE1 and NVE2 and the two NVEs are connected via
   an IP tunnel in the Data Center. A set of tenant systems are
   attached to NVE1 on a server. NVE2 resides on a DC Gateway device.
   NVE2 terminates the tunnel and uses the VNID on the packet to pass
   the packet to the corresponding vGW entity on the DC GW (the vGW is
   the default gateway for the virtual network). A customer can access
   their systems, i.e., TS1 or TSn, in the DC via the Internet by using
   an IPsec tunnel [RFC4301]. The IPsec tunnel is configured between
   the vGW and the customer gateway at the customer site. Either a
   static route or iBGP may be used for prefix advertisement. The vGW
   provides IPsec functionality such as authentication scheme and
   encryption; iBGP protocol traffic is carried within the IPsec tunnel.
   Some vGW features are listed below:

   o  The vGW maintains the TS/NVE mappings and advertises the TS
      prefix to the customer via static route or iBGP.

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   o  Some vGW functions such as firewall and load balancer can be
      performed by locally attached network appliance devices.

   o  If the virtual network in the DC uses different address space
      than external users, then the vGW needs to provide the NAT

   o  More than one IPsec tunnel can be configured for redundancy.

   o  The vGW can be implemented on a server or VM. In this case, IP
      tunnels or IPsec tunnels can be used over the DC infrastructure.

   o  DC operators need to construct a vGW for each customer.

         |   TS1 TSn     |
         |    |...|      |
         |  +-+---+-+    |             Customer Site
         |  |  NVE1 |    |               +-----+
         |  +---+---+    |               | CGW |
         +------+--------+               +--+--+
                |                           *
            L3 Tunnel                       *
                |                           *
   DC GW +------+---------+            .--.  .--.
         |  +---+---+     |           (    '*   '.--.
         |  |  NVE2 |     |        .-.'   *          )
         |  +---+---+     |       (    *  Internet    )
         |  +---+---+.    |        ( *               /
         |  |  vGW  | * * * * * * * * '-'          '-'
         |  +-------+ |   | IPsec       \../ \.--/'
         |   +--------+   | Tunnel

           DC Provider Site

          Figure 1 - DC Virtual Network Access via the Internet

3.2. DC VN and SP WAN VPN Interconnection

   In this case, an Enterprise customer wants to use a Service Provider
   (SP) WAN VPN [RFC4364] [RFC7432] to interconnect its sites with a
   virtual network in a DC site. The Service Provider constructs a VPN
   for the enterprise customer. Each enterprise site peers with an SP
   PE. The DC Provider and VPN Service Provider can build a DC virtual

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   network (VN) and VPN independently, and then interconnect them via a
   local link, or a tunnel between the DC GW and WAN PE devices. The
   control plane interconnection options between the DC and WAN are
   described in RFC4364 [RFC4364]. Using Option A with VRF-LITE [VRF-
   LITE], both ASBRs, i.e., DC GW and SP PE, maintain a
   routing/forwarding table (VRF). Using Option B, the DC ASBR and SP
   ASBR do not maintain the VRF table; they only maintain the VN and
   VPN identifier mappings, i.e., label mapping, and swap the label on
   the packets in the forwarding process. Both option A and B allow VN
   and VPN using own identifier and two identifiers are mapped at DC GW.
   With option C, the VN and VPN use the same identifier and both ASBRs
   perform the tunnel stitching, i.e., tunnel segment mapping. Each
   option has pros/cons [RFC4364] and has been deployed in SP networks
   depending on the applications in use. BGP is used with these options
   for route distribution between DCs and SP WANs. Note that if the DC
   is the SP's Data Center, the DC GW and SP PE in this case can be
   merged into one device that performs the interworking of the VN and
   VPN within an AS.

   The configurations above allow the enterprise networks to
   communicate with the tenant systems attached to the VN in a DC
   without interfering with the DC provider's underlying physical
   networks and other virtual networks. The enterprise can use its own
   address space in the VN. The DC provider can manage which VM and
   storage elements attach to the VN. The enterprise customer manages
   which applications run on the VMs in the VN without knowing the
   location of the VMs in the DC. (See Section 4 for more)

   Furthermore, in this use case, the DC operator can move the VMs
   assigned to the enterprise from one sever to another in the DC
   without the enterprise customer being aware, i.e., with no impact on
   the enterprise's 'live' applications. Such advanced technologies
   bring DC providers great benefits in offering cloud services, but
   add some requirements for NVO3 [RFC7364] as well.

4. DC Applications Using NVO3

   NVO3 technology provides DC operators with the flexibility in
   designing and deploying different applications in an end-to-end
   virtualization overlay environment. Operators no longer need to
   worry about the constraints of the DC physical network configuration
   when creating VMs and configuring a virtual network. A DC provider
   may use NVO3 in various ways, in conjunction with other physical
   networks and/or virtual networks in the DC for a reason. This
   section highlights some use cases for this goal.

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4.1. Supporting Multiple Technologies and Applications

   Servers deployed in a large data center are often installed at
   different times, and may have different capabilities/features. Some
   servers may be virtualized, while others may not; some may be
   equipped with virtual switches, while others may not. For the
   servers equipped with Hypervisor-based virtual switches, some may
   support VxLAN [RFC7348] encapsulation, some may support NVGRE
   encapsulation [RFC7637], and some may not support any encapsulation.
   To construct a tenant network among these servers and the ToR
   switches, operators can construct one traditional VLAN network and
   two virtual networks where one uses VxLAN encapsulation and the
   other uses NVGRE, and interconnect these three networks via a
   gateway or virtual GW. The GW performs packet
   encapsulation/decapsulation translation between the networks.

   A data center may be also constructed with multi-tier zones, where
   each zone has different access permissions and runs different
   applications. For example, the three-tier zone design has a front
   zone (Web tier) with Web applications, a mid zone (application tier)
   where service applications such as credit payment or ticket booking
   run, and a back zone (database tier) with Data. External users are
   only able to communicate with the Web application in the front zone.
   In this case, communications between the zones must pass through the
   security GW/firewall. One virtual network can be configured in each
   zone and a GW can be used to interconnect two virtual networks, i.e.,
   two zones. If the virtual network in individual zones uses the
   different implementations, the GW needs to support these
   implementations as well.

4.2. Tenant Network with Multiple Subnets

   A tenant network may contain multiple subnets. The DC physical
   network needs to support the connectivity for many such tenant
   networks. In some cases, the inter-subnet policies can be placed at
   designated gateway devices. Such a design requires the inter-subnet
   traffic to be sent to one of the gateway devices first for the
   policy checking, which may cause traffic to "hairpin" at the gateway
   in a DC. It is desirable for an NVE to be able to hold some policies
   and be able to forward the inter-subnet traffic directly. To reduce
   the burden on the NVE, a hybrid design may be deployed, i.e., an NVE
   can perform forwarding for selected inter-subnets while the
   designated GW performs forwarding for the rest. For example, each
   NVE performs inter-subnet forwarding for intra-DC traffic while the
   designated GW is used for traffic to/from a remote DC.

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   A tenant network may span across multiple Data Centers that are at
   different locations. DC operators may configure an L2 VN within each
   DC and an L3 VN between DCs for a tenant network. For this
   configuration, the virtual L2/L3 gateway can be implemented on the
   DC GW device. Figure 2 illustrates this configuration.

   Figure 2 depicts two DC sites. Site A constructs one L2 VN, say
   L2VNa, on NVE1, NVE2, and NVE5. NVE1 and NVE2 reside on the servers
   which host multiple tenant systems. NVE5 resides on the DC GW device.
   Site Z has similar configuration, with L2VNz on NVE3, NVE4, and NVE6.
   An L3 VN, L3VNx, is configured on NVE5 at Site A and the NVE6 at
   Site Z. An internal Virtual Interface of Routing and Bridging (VIRB)
   is used between the L2VNI and L3VNI on NVE5 and NVE6, respectively.
   The L2VNI requires the MAC/NVE mapping table and the L3VNI requires
   the IP prefix/NVE mapping table. A packet arriving at NVE5 from
   L2VNa will be decapsulated, converted into an IP packet, and then
   encapsulated and sent to Site Z. A packet to NVE5 from L3VNx will be
   decapsulated, converted into a MAC frame, and then encapsulated and
   sent within Site A. The ARP protocol [RFC826] can be used to get the
   MAC address for an IP address in the L2VNa. The policies can be
   checked at the VIRB.

   Note that L2VNa, L2VNz, and L3VNx in Figure 2 are NVO3 virtual

   NVE5/DCGW+------------+                  +-----------+ NVE6/DCGW
            | +-----+    | '''''''''''''''' |   +-----+ |
            | |L3VNI+----+'    L3VNx       '+---+L3VNI| |
            | +--+--+    | '''''''''''''''' |   +--+--+ |
            |    |VIRB   |                  |  VIRB|    |
            | +--+--+    |                  |   +--+--+ |
            | |L2VNI|    |                  |   |L2VNI| |
            | +--+--+    |                  |   +--+--+ |
            +----+-------+                  +------+----+
             ''''|''''''''''                 ''''''|'''''''
            '     L2VNa     '               '     L2VNz    '
      NVE1/S ''/'''''''''\'' NVE2/S    NVE3/S'''/'''''''\'' NVE4/S
        +-----+---+  +----+----+        +------+--+ +----+----+
        | +--+--+ |  | +--+--+ |        | +---+-+ | | +--+--+ |
        | |L2VNI| |  | |L2VNI| |        | |L2VNI| | | |L2VNI| |
        | ++---++ |  | ++---++ |        | ++---++ | | ++---++ |
        +--+---+--+  +--+---+--+        +--+---+--+ +--+---+--+
           |...|        |...|              |...|       |...|

             Tenant Systems                  Tenant Systems

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                DC Site A                    DC Site Z

         Figure 2 - Tenant Virtual Network with Bridging/Routing

4.3. Virtualized Data Center (vDC)

   An Enterprise Data Center today may deploy routers, switches, and
   network appliance devices to construct its internal network, DMZ,
   and external network access; it may have many servers and storage
   running various applications. With NVO3 technology, a DC Provider
   can construct a virtualized DC over its physical DC infrastructure
   and offer a virtual DC service to enterprise customers. A vDC at the
   DC Provider site provides the same capability as a physical DC at
   the customer site. A customer manages their own applications running
   in their vDC. A DC Provider can further offer different network
   service functions to the customer. The network service functions may
   include firewall, DNS, load balancer, gateway, etc.

   Figure 3 below illustrates one such scenario. For simplicity, it
   only shows the L3 VN or L2 VN in abstraction. In this example, the
   DC Provider operators create several L2 VNs (L2VNx, L2VNy, L2VNz) to
   group the tenant systems together on a per-application basis, and
   one L3 VN (L3VNa) for the internal routing. A network firewall and
   gateway runs on a VM or server that connects to L3VNa and is used
   for inbound and outbound traffic processing. A load balancer (LB) is
   used in L2VNx. A VPN is also built between the gateway and
   enterprise router. The Enterprise customer runs Web/Mail/Voice
   applications on VMs at the provider DC site which may be spread
   across many servers. The users at the Enterprise site access the
   applications running in the provider DC site via the VPN; Internet
   users access these applications via the gateway/firewall at the
   provider DC.

   The Enterprise customer decides which applications should be
   accessible only via the intranet and which should be assessable via
   both the intranet and Internet, and configures the proper security
   policy and gateway function at the firewall/gateway. Furthermore, an
   enterprise customer may want multi-zones in a vDC (See section 4.1)
   for the security and/or the ability to set different QoS levels for
   the different applications.

   The vDC use case requires the NVO3 solution to provide DC operators
   with an easy and quick way to create a VN and NVEs for any vDC
   design, to allocate TSs and assign TSs to the corresponding VN, and
   to illustrate vDC topology and manage/configure individual elements
   in the vDC in a secure way.

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                           Internet                    ^ Internet
                              ^                     +--+---+
                              |                     |  GW  |
                              |                     +--+---+
                              |                        |
                      +-------+--------+            +--+---+
                      |Firewall/Gateway+--- VPN-----+router|
                      +-------+--------+            +-+--+-+
                              |                       |  |
                           ...+....                   |..|
                  +-------: L3 VNa :---------+        LANs
                +-+-+      ........          |
                |LB |          |             |     Enterprise Site
                +-+-+          |             |
               ...+...      ...+...       ...+...
              : L2VNx :    : L2VNy :     : L2VNz :
               .......      .......       .......
                 |..|         |..|          |..|
                 |  |         |  |          |  |
               Web Apps     Mail Apps      VoIP Apps

                        Provider DC Site

                   Figure 3 - Virtual Data Center (vDC)

5. Summary

   This document describes some general and potential NVO3 use cases in
   DCs. The combination of these cases will give operators the
   flexibility and capability to design more sophisticated cases for
   various cloud applications.

   DC services may vary, from infrastructure as a service (IaaS), to
   platform as a service (PaaS), to software as a service (SaaS).
   In these services, NVO3 virtual networks are just a portion of such

   NVO3 uses tunnel techniques to deliver VN traffic over an IP network.
   A tunnel encapsulation protocol is necessary. An NVO3 tunnel may in

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   turn be tunneled over other intermediate tunnels over the Internet
   or other WANs.

   An NVO3 virtual network in a DC may be accessed by external users in
   a secure way. Many existing technologies can help achieve this.

   NVO3 implementations may vary. Some DC operators prefer to use a
   centralized controller to manage tenant system reachability in a
   virtual network, while other operators prefer to use distribution
   protocols to advertise the tenant system location, i.e., NVE
   location. When a tenant network spans across multiple DCs and WANs,
   each network administration domain may use different methods to
   distribute the tenant system locations. Both control plane and data
   plane interworking are necessary.

6. Security Considerations

   Security is a concern. DC operators need to provide a tenant with a
   secured virtual network, which means one tenant's traffic is
   isolated from other tenants' traffic as well as from non-tenants'
   traffic. DC operators also need to prevent against a tenant
   application attacking their underlying DC network through the
   tenant's virtual network; further, they need to protect against a
   tenant application attacking another tenant application via the DC
   infrastructure network. For example, a tenant application attempts
   to generate a large volume of traffic to overload the DC's
   underlying network. An NVO3 solution has to address these issues.

7. IANA Considerations

   This document does not request any action from IANA.

8. References

8.1. Normative References

   [RFC7364] Narten, T., et al "Problem Statement: Overlays for Network
             Virtualization", RFC7364, October 2014.

   [RFC7365] Lasserre, M., Motin, T., and et al, "Framework for DC
             Network Virtualization", RFC7365, October 2014.

8.2. Informative References

   [IEEE 802.1Q]  IEEE, "IEEE Standard for Local and metropolitan area
             networks -- Media Access Control (MAC) Bridges and Virtual
             Bridged Local Area", IEEE Std 802.1Q, 2011.

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Internet-Draft               NVO3 Use Case                 October 2015

   [NVO3HYVR2NVE] Li, Y., et al, "Hypervisor to NVE Control Plane
             Requirements", draft-ietf-nvo3-hpvr2nve-cp-req-01, work in

   [NVO3ARCH] Black, D., et al, "An Architecture for Overlay Networks
             (NVO3)", draft-ietf-nvo3-arch-02, work in progress.

   [NVO3MCAST] Ghanwani, A., "Framework of Supporting Applications
             Specific Multicast in NVO3", draft-ghanwani-nvo3-app-
             mcast-framework-02, work in progress.

   [RFC1035] Mockapetris, P., "DOMAIN NAMES - Implementation and
             Specification", RFC1035, November 1987.

   [RFC1631] Egevang, K., Francis, P., "The IP network Address
             Translator (NAT)", RFC1631, May 1994.

   [RFC4301] Kent, S., "Security Architecture for the Internet
             Protocol", rfc4301, December 2005

   [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
             Networks (VPNs)", RFC 4364, February 2006.

   [RFC7348]  Mahalingam,M., Dutt, D., ific Multicast in etc "VXLAN: A
             Framework for Overlaying Virtualized Layer 2 Networks over
             Layer 3 Networks", RFC7348 August 2014.

   [RFC7432]  Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A. and
             J. Uttaro, "BGP MPLS Based Ethernet VPN", RFC7432,
             February 2015

   [RFC7637] Garg, P., and Wang, Y., "NVGRE: Network Virtualization
             using Generic Routing Encapsulation", RFC7637, Sept. 2015.

   [VRF-LITE] Cisco, "Configuring VRF-lite",


      Vinay Bannai
      2211 N. First St,
      San Jose, CA 95131
      Phone: +1-408-967-7784

Yong, et al.                                                  [Page 14]
Internet-Draft               NVO3 Use Case                 October 2015

      Ram Krishnan
      Brocade Communications
      San Jose, CA 95134
      Phone: +1-408-406-7890

      Kieran Milne
      Juniper Networks
      1133 Innovation Way
      Sunnyvale, CA 94089
      Phone: +1-408-745-2000


   Authors like to thank Sue Hares, Young Lee, David Black, Pedro
   Marques, Mike McBride, David McDysan, Randy Bush, Uma Chunduri, and
   Eric Gray for the review, comments, and suggestions.

 Authors' Addresses

   Lucy Yong
   Huawei Technologies

   Phone: +1-918-808-1918

   Mehmet Toy
   1800 Bishops Gate Blvd.,
   Mount Laurel, NJ 08054

   Phone : +1-856-792-2801
   E-mail :

   Aldrin Isaac

   Vishwas Manral

Yong, et al.                                                  [Page 15]
Internet-Draft               NVO3 Use Case                 October 2015

   Ionas Networks


   Linda Dunbar
   Huawei Technologies,
   5340 Legacy Dr.
   Plano, TX 75025 US

   Phone: +1-469-277-5840

Yong, et al.                                                  [Page 16]